A similar respirator is disclosed in the German Offenlegungsschrift 3,324,222. The known respirator operates by recycling. The arrangement provides a chemical cartridge lying in the respiratory passage. Such a respirator has two chemical fillings, which are disposed in parallel and, starting out from the mouthpiece, are supplied with the exhaled air of the wearer of the respirator. The exhaled air passes through a connecting pipe and reaches a manifold chamber, from which it is distributed into the two chemical fillings. In the chemical fillings, the exhaled air is freed from carbon dioxide and water and enriched with oxygen. After passing through the chemical fillings, the enriched, respired air is combined in a common exhaled air bag. From there, it reaches the mouthpiece directly when the wearer of the respirator breathes in. The cyclic respiration is assured by the appropriate insertion of check valves in the respirator tubes, so that the chemical fillings are always supplied during an exhalation and the prepared amount of respiratory air is taken directly from the breather bag during an inhalation.
Admittedly, the parallel arrangement of several chemical fillings enables the period of use of such a respirator to be extended. This is due to the fact the amount of chemicals regenerating the respired air is increased and yet the resistance to breathing remains low. However, it is not possible to guarantee that the chemical fillings, which are connected in parallel, are supplied uniformly with air during their period of use. Due to the different resistances to flow that result from different flow conditions of the breath in the individual beds or also due to the different lengths of the paths of flow of the respired gas through the differently supported beds, one of the fillings is supplied preferentially with air. The filling supplied with air is the one which offers the least resistance to the flow of the respired gas. As a result, however, the bed in question is also consumed more rapidly than the other and is blanketed by the consumed chemicals. Then, however, one less chemical filling less is available for the further respiration, the breathing resistance increases and the advantage of the parallel supply of air to several chemical fillings is given up prematurely.